1. Field of the Invention
The invention lies in the field of packaging technology and relates to a method and to an installation. The method and installation serve for packaging flat objects, for example individual printed products, stack-like groups of printed products, or stack-like groups of printed products and other flat items, such as for example CDs, flat product samples or flat sample bags.
2. Description of Related Art
It is known to package flat objects of the above mentioned type with the help of a quasi endless packaging material web (e.g. plastic film or paper web supplied from the roll). Thereby, such a packaging material web is folded around a row of the objects, in which the objects are conveyed one after the other and distanced from each other. Alternatively, two packaging material webs are supplied to such a row, one from each side. The packaging material web (or webs) is then closed around the row in longitudinal seams on the upper side of the row or laterally thereto, and in transverse seams between each two successive objects. As the case may be, the objects which are such enclosed on all sides by packaging material are separated from one another directly after the transverse seams are made or simultaneously with the making of these seams.
If a plastic film is used as packaging material, the longitudinal and transverse seams are usually made by welding, wherein the separation of the packaged objects may be carried out simultaneously with the welding. If the packaging material is paper, an adhesive to be activated by heat may be deposited onto the packaging material in the locations of the longitudinal and transverse seams, directly before the web is supplied to the row of objects to be packed. The seams are then made with similar means as used for welded seams on plastic packaging material. It is also possible to close the seams by way of embossing or by way of other known methods which are matched to the packaging material which is used.
Devices for implementing packaging as mentioned above are for example disclosed in the publications EP-01712782, DE-3123988 or EP-0018041.
As disclosed in these publications, the objects are supplied to be packaged lying loosely on a conveyor surface (e.g. conveyor belt) in a row, in which they are arranged one after the other and distanced from one another. The distances between successive objects is adapted to the thickness of the objects and to the applied methods for making the transverse seams and for separating the packaging material. For maintaining the exact arrangement of the objects in the row, conveyor cams are used in addition to the conveyor surface, by way of which the flat objects can be supplied in a more accurately cycled manner than would be the case with the conveyor surface as a sole conveyor means. The quasi endless packaging material web is then supplied to the row of flat objects either from below through a gap in the conveyor surface or from above, wherein the packaging material web has the same speed as the row of the objects.
For creating the row, the objects are usually separated from a stack and laid individually onto the conveyor surface.
In practice, the mentioned packaging method including establishing and supplying the object row requires a relatively long conveyor path, which for reasons of available space can in many cases only be realised including changes in the conveying direction. In such direction changes, acceleration forces not only effect the flat objects in a disorientating manner, but also have a destabilising effect on objects, in particular if these objects are stacks of a plurality of flat items. Additionally, when the conveying capacities are high, there are high conveyor speeds and due to this, high air resistances, which have the same effect on the objects. In order to be able to counteract such effects, extensive measures are necessary on the part of the installation, by way of which the required conveyor paths are usually extended even more.
It is, therefore, the object of the invention to create a method and an installation which serve for packaging a row of flat objects with the help of a quasi endless packaging material web, and with which the disadvantages of known such methods and installations as described above can be avoided. In particular, the method and installation according to the invention are to enable limitation of the conveyor paths to a minimum length, and to make do with the simplest of conveyor means, and despite of this to be able to package at high conveyor performance even objects having only little stability.